Alpha-lipoic acid

What is alpha-lipoic acid?

Alpha-lipoic acid (ALA) is a sulfur-containing compound that the body makes in small amounts and uses in the mitochondria to help convert food into energy. It is also found in foods such as spinach, broccoli, potatoes and organ meats. Unlike many antioxidants, ALA works in both water and fat, and it helps regenerate other antioxidants such as vitamins C and E.

Not to be confused with alpha-linolenic acid (an omega-3 fat that shares the same abbreviation), alpha-lipoic acid is sold as a supplement for blood sugar support, nerve health and general antioxidant protection.

What the research says

Most clinical research on ALA focuses on diabetic peripheral neuropathy, the tingling, burning nerve pain that affects many people with diabetes. In those trials, ALA (often 600 mg per day, sometimes given intravenously) has shown modest improvements in symptoms in some studies. Evidence for blood sugar control itself is mixed.

For erectile function, research is thin. Small studies have examined ALA in men with diabetes and erectile problems, typically alongside other treatments, and a systematic review was planned in 2020 to look at the question. Animal research suggests ALA may help blood vessel function, but this has not been confirmed in good human trials for sexual performance.

On safety, the evidence is reassuring. A 2020 systematic review and meta-analysis pooled 71 randomized placebo-controlled studies with more than 4,700 participants and found that ALA supplementation was not associated with an increased risk of adverse events, including in subgroups with diabetes, heart disease and kidney impairment.

How it’s used in supplements

ALA is common in blood sugar formulas, nerve support products and “anti-aging” blends. Studied doses usually range from 300 to 600 mg per day, sometimes higher. Some products use the R-form (R-ALA), which is the natural form; most use a 50/50 mix of R and S forms.

A dose of 150 mg is below the range used in most trials. ALA is generally well tolerated, with occasional nausea, heartburn or skin rash. Because it may lower blood sugar, people taking insulin or other diabetes medication should monitor glucose. ALA may also affect thyroid hormone treatment, and high doses could theoretically be a concern in people with thiamine (vitamin B1) deficiency, such as heavy drinkers. Talk to your doctor before use if any of these apply.

Bottom line: alpha-lipoic acid has a good safety record and a plausible role in nerve and blood vessel health, but its benefits have been shown mainly at higher doses in people with diabetes. Anyone hoping it will improve erections should know that this has not been established in quality human trials.